This invention relates to nylon foams and a method of producing same, in particular, it relates to a foam produced by means of the mechanical frothing of a nylon block copolymer material.
Nylon 6 block copolymers (NBC) are a class of polymers based on the anionic polymerization of caprolactam with polymeric polyols. In general, the system utilizes di-functional imides which act as coupling agents between polyol and nylon blocks, as well as functioning as activated sites for caprolactam polymerization.
In the production of Nylon 6 block copolymers, two reactant streams are brought together, mixed and finally injected under pressure into a mold wherein polymerization and development of resin properties are essentially achieved. The first of the two reactant streams comprise a catalyst dissolved in molten caprolactam, and the second comprises a prepolymer of a polyol reacted with a bisimide in molten caprolactam.
The NBC system so produced may be modified in a number of ways and find extensive use in reaction injection molding operation, in that such a system yields products generally characterized by a good impact strength/stiffness balance and a relatively flat modular temperature response.